1. Technical Field
The present invention relates to a method for manufacturing metal nanoparticles including rod-shaped nanoparticles, more particularly, to a method for manufacturing metal nanoparticles that can control size of metal nanoparticles to several nm and shape of metal nanoparticle to rod shape.
2. Description of the Related Art
In response to demands for electronic components with miniaturization and high-densification, needs for metal patterning in a thin film using inkjet or formation of microwiring on a substrate have been increased. To implement this, it is necessary to produce conductive ink which is made from nano size of copper particles having a uniform shape, a narrow distribution of particles and an excellent dispersibility.
There are various methods of producing copper nanoparticles, such as mechanical grinding method, co-precipitation method, spray, sol-gel method, electro-deposition method, and microemulsion method, etc. In case of producing metal nanoparticles by the co-precipitation method widely used, it is impossible to control size, shape, size distribution of particles. In case of producing by the electro-deposition method and sol-gel method, it is difficult to produce in mass production and production cost is high. Also, in case of producing by the microemulsion method, it is easy to control size, shape, size distribution of particles, however, it is not suitable for practical use as the production process is complicated.
A method for nanoparticle in solution has a restriction for concentration. In other words, preparing nanoparticles with uniformity in size is achieved below 0.01M and productivity is also unpreferable. Thus, to preparing nanoparticles with uniformity in size, a reactor with size of 1000 L is required.
Also, conventional methods for manufacturing nanorod metal particles are laser ablation method and chemical vapor deposition, etc. These methods control materials to be synthesized and catalyst with proper ration and perform vaporization using high temperature and laser. However, the above methods require high-cost apparatus and, also have limitations for controlling particle size since it is difficult to not only control the size of particles finely but also produce particles with a desired dispersibility.
Besides the above methods, methods that are conducted in solution are a AAO (Anodized Aluminum Oxide) method that prepares 1-dimension wire by using aluminum as a substrate and a particle synthesis that uses porous materials such as MCMs (MCM-41, MCM-48) and zeolite, etc. Such porous materials are not proper for controlling size, dispersion and recovering of particles.